This application is based upon, claims the benefit of priority of, and incorporates by reference, the contents of Japanese Patent Application No. 2002-124140 filed Apr. 25, 2002.
1. Field of the Invention
The present invention relates to a composite auxiliary machine for a vehicle and a control unit thereof suitably applied to a refrigeration cycle device installed in a vehicle with an idling-stop function, which stops the vehicle engine when the vehicle temporarily stops.
2. Description of the Related Art
Vehicles with an idling-stop function have recently appeared on the market to increase vehicular fuel efficiency. Since this type of vehicle stops its engine temporarily when a vehicle makes a temporary stop, a refrigeration cycle device compressor that is driven by the engine, also stops. Thus, the refrigeration cycle device can not operate as a cooling device while the engine is stopped.
In order to solve this problem, Japanese Patent Laid-Open Publication No. Hei 9-324668 discloses composite auxiliary machines in which an engine crank pulley having a crank clutch is connected to a compressor and a rotary machine with a belt. Operation of the compressor and the rotary machine is controlled in accordance with operating conditions of the engine.
To be more specific, the rotary machine functions as both, an electric motor and a generator. When the engine operates, the crank clutch is engaged, so that the driving force of the engine operates the compressor and the rotary machine to carry out cooling operations and electric power generation.
On the other hand, when the engine stops, the crank clutch disengages. Then, the rotary machine is operated as an electric motor to operate the compressor, so that continuous cooling is possible by continuing the cooling operation. Since the rotary machine is also used as a starter, which is the electric motor needed for starting the engine, it is not necessary to install an additional electric motor.
The above-described device has a problem, however, in that the length of the engine becomes long because the engine is equipped with the crank clutch. The long engine makes its installation difficult. Accordingly, a composite auxiliary machine has been considered in which the compressor is directly connected to the rotary machine, and either the compressor or the rotary machine has a clutch function. In this case, however, it is impossible to obtain desirable startup performance, because when the rotary machine is used as an electric starting motor to rotate the engine, the output of the rotary machine decreases under the operational load of the compressor which rotates together with the engine.
An object of the present invention is to provide a composite auxiliary machine for a vehicle and a corresponding control unit thereof which both have a desirable startup performance when the engine is started.
To achieve the above object, the present invention employs the following technical means. A composite auxiliary machine for a vehicle according to a first aspect of the present invention includes a compressor (140), a rotary machine (130), a drive pulley (110), and intermittent means (120). The compressor (140) compresses a refrigerant inside a refrigeration cycle device (200). The rotary machine (130), functioning as both a generator and an electric motor, is connected to the compressor (140) and rotates together with the compressor (140). The drive pulley (110) rotates in response to a driving force from a vehicle engine (10) to actuate the compressor (140) or the rotary machine (130). The intermittent means (120) is provided between the drive pulley (110) and the compressor (140), or between the drive pulley (110) and the rotary machine (130) to transmit and terminate the driving force of the drive pulley (110). The compressor (140) has a variable displacement mechanism (145, 148) which varies in amount of discharge per revolution.
In the composite auxiliary machine (100) for a vehicle, when the vehicle engine (10) is operated, the engagement of the intermittent means (120) operates both the compressor (140) and the rotary machine (130). When the refrigeration cycle device (200) is driven, the rotary machine (130) functions as the generator.
When the vehicle engine (10) stops, the intermittent means (120) is disengaged. The rotary machine (130) is operated as the electric motor to operate the compressor (140), so that it is possible to continue cooling operations.
When the rotary machine (130) is operated as an electric motor to actuate the vehicle engine (10), the variable displacement mechanism (145, 148) of the compressor (140) decreases its amount of discharge. Thereby, the operational load of the compressor (140) decreases so that it is possible to prevent reduction in the output of the rotary machine (130). In other words, it is possible to obtain the desirable startup performance of the vehicle engine (10). Continuing, it is possible to reduce power consumption of the rotary machine (130) and also to reduce the physical size of the rotary machine.
According to a second aspect of the invention, the variable displacement mechanism (145, 148) can arbitrarily vary the amount of discharge within a range from the maximum amount of discharge of the compressor (140) itself to the minimum amount of discharge, which is almost zero.
Accordingly, it is possible to minimize the operational load of the compressor (140) on the rotary machine (130), since the amount of discharge of the compressor (140) is minimized, almost zero, when the vehicle engine (10) is started.
According to a third aspect of the invention, the drive pulley (110) and the intermittent means (120) are provided on the rotary machine (130), and a limiter mechanism (150) is provided between the compressor (140) and the rotary machine (130) to disengage the connection between the compressor (140) and the rotary machine (130), when the compressor (140) is locked. Accordingly, the vehicle engine (10) and the rotary machine (130) are protected when the compressor (140) is locked. Therefore, functions related to the drive are not impaired.
According to a fourth aspect of the invention, the drive pulley (110) and the intermittent means (120) are provided on the rotary machine (130), and a reduction mechanism (160), which slows down the RPM of the rotary machine (130) and transmits the rotary motion thereof to the compressor (140), is provided between the compressor (140) and the rotary machine (130). Accordingly, the reduction mechanism (160) reduces the RPM of the compressor (140) as compared with that of the rotary machine (130), when the driving force of the engine (10) is transmitted. Therefore, the compressor (140) will have the proper RPM.
According to a fifth aspect of the invention, a dumping section (170) for absorbing the torque fluctuations of the compressor (140) is disposed between the compressor (140) and the rotary machine (130). Thus, it is possible to prevent breakage of the rotary machine (130) by preventing resonance of a rotary machine shaft (132) with the rotary machine (130).
According to a sixth aspect of the present invention, a control unit of a composite auxiliary machine for a vehicle includes the composite auxiliary machine (100) according to any one of the foregoing first to fifth aspects, and control means (180) for controlling the amount of discharge of the compressor (140), the operation of the rotary machine (130), and the engagement and disengagement of the intermittent means (120). When the vehicle engine (10) is started, the control means (180) controls in order to engage the intermittent means (120) and operate the rotary machine (130) as an electric motor for actuating the vehicle engine (10). Also the control means (180) controls in order to make the amount of discharge from the compressor (140) smaller than that necessary in the refrigeration cycle device (200).
According to a seventh aspect of the invention, it is preferable that the amount of discharge described above is reduced to almost zero. Thus, it is possible to obtain the same effect as the first to fifth aspects of the invention described above.
Reference numerals described in each of the above means correspond to the embodiments described in the Detailed Description of the Preferred Embodiments. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.